Control device for vehicle suspension



March 22, 1960 N. B. CHRISTENSEN 2,929,619

CONTROL DEVICE FOR VEHICLE SUSPENSION Filed Feb. 13, 1956 2 Sheets-Sheet l March 22, 1960 N. B. CHRISTENSEN 2,929,619

CONTROL DEVICE FOR VEHICLE SUSPENSION Filed Feb. 13, 1956 2 Sheets-Sheet 2 INVEN TOR. NORMAN B. CHRISTENSEN BY Wuw United States Patent CONTROL DEVICE FOR VEHICLE SUSPENSIN This invention relates generally to suspension systems for vehicles. More particularly, the invention relates to pneumatic suspension systems and provides means whereby pneumatic devices, such as bellows type air springs, may be made to respond to increased or decreased vehicle loads causing a substantial change in the riding level of the vehicle, and yet prevent unnecessary alteration of the riding level when the vehicle road gear passes over a bump or drops into a hole, which actions only momentarily alter the load on the suspension system.

Pneumatic suspension systems, incorporating air springs interposed between the vehicle frame and road or running gear, have been slow to achieve commercial success because they have not been provided with satisfactory valve means for controlling and regulating the air cushion within the air springs. Maintaining a constant average air spring length or air cushion under variable static load conditions, will provide a constant riding level for the vehicle.

A satisfactory valve means for eectively controlling the riding level of a vehicle having an air spring suspension, must be responsive to changing static load conditions. An increase in the load will compress the air spring. To restore the air spring to its initial position, air under increased pressure must be admitted into the air spring. A decrease in load will cause the air spring to extend or raise, and therefore, air must be exhausted or vented from within the air spring to restore it to its initial position.

In addition to controlling the supply `and exhaust of air to and from an air spring, a satisfactory valve control means must embody therein an adjustable timeY delay so that momentary alteration of the static load on the suspension system, such as would be encountered during normal axle movement due to road irregularities, will not cause the valve to supply or exhaust air. This time delay feature is often referred to as damping and preferably is adjustable over a time range of from 1 to 20 seconds, as determined by the weight of the vehicle, road conditions, etc.

The operation of the valve means also must not be influenced by the natural frequency of the vehicle suspension system which will probably be in the range of from l to 2 cycles per second.

Lastly, a satisfactory valve and its control means must be unaifected by and remain operative under extremes of temperature, humidity and exposure to sand, dirt, grease, oil and water.

it is therefore an object of this invention to provide an improved pneumatic suspension system for vehicles, which system includes improved valve and valve control means for controlling and regulating air springs interposed between the vehicle frame and road gear, so as to furnish a constant riding level for the Vehicles and a constant average air spring length.

Another object is to provide an improved valve and control means for control and regulation of a vehicle air spring suspension, which controls the supply and exfice haust of air to the air springs, hasa novel time delay or damping feature, and is operative under extremes of temperature, humidity and other environmental conditions.

A further object is to provide an improved valve and control means located remotely of the air springs and embodying therein a novel adjustable time delay or damping component to prevent excessive operation of the valve, which is accurately responsive to persistent changes in vehicle loading, and which is of simple, relatively uncomplex construction.

A further object is to provide a novel time delay or damping mechanism for use with an air spring control valve.

These and other objects will be apparent in view of the following detailed description of the invention considered with the attached drawings.

in the drawings:

Fig. 1 is a vertical sectional view through a vehicle axle showing in elevation a portion of the vehicle equipped with a pneumatic suspension system according to the invention;

Fig. 2 is a top plan view of a valve and control means according to the invention;

Fig. 3 is an enlarged sectional view, taken substantiallyv on line 3-3 of Fig. 2;

Fig. 4 is a similar sectional view taken substantially on line 4 4- of Fig. 3;

Fig. 5 is a fragmentary sectional view of a portion of Fig. 3, showing the valve and control means in an air exhaust position;

Fig. 6 is a fragmentary sectional view of the valve and control means actuating shaft in a momentarily displaced position;

Fig. 7 is a further enlarged sectional view of the parts shown in Figs. 3 and 5, showing the valve and control means in an air supply position; and

Fig. 8 is a fragmentary sectional view, taken substantially on line 8 3 of Fig. 7, certain elements being omitted for clarity of illustration, the view being rotated approximately 45.

In the present invention a ride control valve means, indicated generally by the numeral 1%, includes a housing 11, generally rectangular in cross section, which carries a damping means, and an air supply and exhaust control means. The housing 11 is located remotely and laterally of a conventional air spring bellows 12, of multiply rubber and cord construction and having one or more convolutions 13. The upper end of the air spring is hermetically fastened by a suitable clamp ring 14 to the underside of a horizontal transverse member 15 constituting a portion of the vehicle frame. The member 15 is securely aixed at either end to longitudinal frame members 16. The lower end of the air spring 12 is also hermetically fastened by a similar clamp ring 14 to the upperside of a bracket 17 on the axle housing 1S of the vehicle road gear. One mode of interposing an air spring between a vehicle frame and road gear has been shown and described. It will be understood, however, that the principles of the invention are applicable to air springs interposed in other ways between the frame and road gear. Also, only one air spring has been shown in connection with this invention, but it Will be understood that the invention may be utilized with as many air springs as are required on a vehicle.

A stub ange 2t) which may be located atop the vehicle differential housing 21, has a bolt 22 therethrough, which bolt extends through an elongated longitudinal slot 23 formed in the lower end of a control valve actuating rod 24, so that rod 24 is slidably mounted on bolt 22. The upper end of the actuating rod is fixed to one end of a control valve actuating shaft 25 and secured thereon by a nut 26,`said shaft being mounted for rotation in housing 11 in a manner to be described. The housing 11 preferably is located above and to the rear of the horizontal Vplaneiof'thef axle, and is-fastenedfby kb olts 27 toabase bracketfZS. The bracket 28 isfastened'v byboltsY` 29-tofa frame/member@fextendingjtransversely ofand,

secured to the'longitudinal frame members 16.

Air,Y from; al source under pressure (not shown), is

interior of the air spring. The piping'34is the conduit .for supplyingv air `to andrexhausting air from the Vair an O-ring seal 65 which limits passage of air downward along the piston rods, 61 and V62, and passage of hy- The control device is conspring ,'12, through the control device 16, as referred to later. t Y

Referring to Figs.v 7 and f8, at one end of the lhousing 11 is an air exhaust port V36. whichv ventsY from within the housing to the atmosphere. At the opposite end o', the housing is an Vair supply port 37 intowhich a fitting 38, `attached tothe piping 32, is tightly secured. On 4one side of the housing- 11, adjacent the'exhaust port 36 and communicating therewith interiorly of theV housing, as described later, is a two-way port 39 into'which a fitting 40, attached tothe piping 34, is tightly secured.

The air supply port 37 opens through a short lateral passage 41 into a verticali boreYV 42, which has a reducedv area or orifice 43 communicating withan upper enlarged' v chamber 44. The chamber f4-communicates through an upwardly extending diagonal passage 45 with a longitudinal passage 46 extending-acrossthe upper portion of the housing 11. The passage46 communicates through a downwardly extending diagonal passage 47 with a second `vertical boreAS, similar to bore 42,. Bore 48 has a reduced area ororiiice 49, similar to area-43, which com- Amunicates with an' upper enlarged chamber 50, similar to chamber 44. Below the area 49, a short lateral passage 51 (Fig; 8) connects the port 39 with bore 48. The chamber Si) communicates/.With the air exhaust port 36 through a downwardly extending diagonal passage 52. The upper ends of the chambers 44 and 50, and the passage 46, are closed by a plate 53 extending longitudinally of theV housing and tightlyrsecured thereto by bolts 54.V

Elements 36-53, just described dene'the paths in,-

teriorly of the valve housing 11, through which air passes from the supply port 37 to the two-way port 39,

and from the latter port to the exhaust port 36.

The passage-of airv interiorly of the'valveY housing i1 is .-contrrolledeby valves 56V and 57, `in the form of flat, reinforced, air impermeable discs seated withinchambers Y 44 and 50, respectively, against the upperends of orices 43 and 49, andV backed by valve springsV 53 and 59 seated at their upper end against the plate4 53. In the embodiment of the invention shown, the strength of Vthese valve springs is always greater than the pressure of the air in the piping 32 and 34, so that the valves are Valways tending to close the oriiices 43 and 4 9, preventing passage of air past the valves into the chambers 44 and Si). V

Obviously, the exhaust and supply ports 36 and 37 could be reversed, inwhich case the valve springs 5S Yand 59 need not be ofV a strength greater than the pires-V upper end portion, 63. and 64, adapted to move through orificesV 43 and 49,k respectively, so as toy lift valves 56 and 57 from their normal seats, at the lower end of chambers. 44 andil., Each bore, 42and 48, isttedwith hthat terminates in a further enlargedhead 66'.

formed in housingY i1 Ybelow bores 42 -and 48, respectively. V

Y Each piston 166 'comprises an end'plate, '67 and 68, respectively, bearing against head 6 6', a resilient cup 71,

. resistant to hydraulic fluid and havingY side portions 71A engaging the sides of bores 69 and 7G to form an oil tightseal, and anv innerfplate72 engagingzthe-bottom of each cup. A compression spring `73 is arranged between each plate 72 and the top of each, cylinder bore, respectively. Springs 73 hold the cups and Ypiston plates in proper position -with respect to pistonl heads66.

Each bore, 69-and 70, .filledcompletely with a suitable liquidy such as hydraulic brake iluid yabove the piston platesk 72. As described later, movement of one piston irrone direction, up orr dowmproducesa movement of the other piston inthe oppositeV direction, withconsequent-inoyernentA of thepiston rods. This resultisobtained-v by providingga-.conduit or passageway through the valve housing 11 connecting. bores 69.*and 70 a slight distance below the top ofeachbore. Referring to Figs. 4 and 7, a short lateral passage 76V connects therbore 69 with a vertical passage 77, which'in turncommunicates withr az transverse passage-78. The latter p assage comrnunicatesA with a verticalf passage Y 82, which in turn communicates with a short'passage 83r openinginto bore 7i?. To regulate the flow o f-,uid through thepassage 7S, thereby controlling the rate, at which Huid can be displaced from within bore 69 to within bore 7i), or vice versa as the case may be, anadjustableneedle valve-8i) is inserted intoY a short passage lextending horizontally through thewall ofthe valve housing 11, into the passage 7S'. Movementof the needle valve 80 into the passage 7S will provide reductionin the rate at which a given quantity ofl fluid, will movek therethrough. Conversely, movementof the needle valve 8i) out ofthe-passage 7S will permitanincrease inthe rate offluidow.,

Movement of the 'pistonl rods and pistons isA effected by componentsiofthemeans,tlwhich are actuated by the shaft 25, As more clearly shown 1in Figs.V 2, and 4,

the actuating shaft ZVS/extends through the medial portion of thevalvehousing.y The endof the shaft fastened to theactuating-.rod124 is journaled in a boss 85 on the side of the housing 11 oppositefof the port39; The other end ofthe shaft is journaled in a similar bossV 36 on ther-other side ofjthe housing. Both ends of the shaft 25 are round so as to rotate freely inits bearings. However, withinthe'valve housingll, the shaft is generally semicircular in section, having a flattened surface-2SA.

rhe actuating shaftv25 extends transversely through the lower portion of al vertical cylindrical bore 9i? located between the damping piston-bores 69 and 70. The height of thelbore 9i) is greater than that of the bores@ and tland shares with them common wall sections 91 at its lower end.

Within the bore-96 is a plunger cupA 9,2', having a closed lower endl 9 3 which contacts thershaftES and is ably contained within the shaft follower cup 95. The open lower end of the follower cup 95 is provided with a ange 96a, to which is rigidly secured, on opposite sides thereof, a pair of piston actuating bars, 97 and 98. The follower cup 95 and the actuating bars 97 and 98 define an oscillating member which, when actuated by the rotating shaft 25, selectively contact the piston heads 66. Adjacent the vertical sides 99 of the follower cup 95, each of the actuating bars 97 and 98 is provided with a recessed groove 199, so that rocking movement of the actuating bars is unhindered by the wall sections 91 lof the valve housing.

The operation of the control device is as follows:

Let us assume that the normal static load on the vehicle suspension requires the air springs to be inated to a pressure of about 50 p.s.i., in which condition the valves 55 and 57 are in the position shown in Fig. 3, that is, seated atop the restricted orifices 43 and 49 and preventing air from passing through the chambers 44 and 50. rfhis normal position of the valves is brought about because, in the preferred embodiment shown, the valve springs 5S and 59 are so engineered as to always be tending to seat the valves and close the orices.

Now then, assume that the static load is increased, for example, by adding merchandise or passengers to the vehicle. As the load is increased, the upper frame members and 16 move downwardly toward the axle housing 1S,- causing the air spring 12 to contract. During this downward movement of the upper frame members, the frame member 30 and the control device 10 also move downwardly. Such downward movement of the control device 10, causes the actuating shaft 25 to be turned by the actuating rod 24, the lower end of which is slidably attached to the differential housing, to permit sliding movement of the rod as the device '1G moves downwardly. That is, as the distance between the member 15 and the axle housing 1S decreases, the rod 24 will cause the shaft 25 to be rotated within the valve housing 11.

As viewed in Fig. l, an increased load would cause the shaft 25 to rotate in a counter-clockwise direction to supply air under pressure into the air spring 12. Referring specifically to Fig. 7, as the shaft 25 is rotated counter-clockwise on its axis, transverse of the bore 90, the plunger cup 92 will be displaced upwardly within the follower cup 95, compressing furtherA the follower spring 94. As the spring 94 is compressed, energy stored therein becomes directed substantially equally between the lower end 93 of the plunger and the upper end 96 of the follower. The plunger end is fixed by the shaft and cannot be displaced downwardly though it will immediately do so in the event the shaft 25 is rotated back even a small degree in a clockwise direction. However, within certain limits, the follower cup 95 can be displaced laterally within the bore 9G away from the shaft 25. Therefore, as the spring 94 is compressed, the follower cup 95 will be caused to rotate on the same axis as that of the shaft 25 and be displaced upwardly to assume the position shown in Fig. 7. rihat is, the follower cup will turn counter-clockwise until the left hand corner of the upper end 96 contacts the side wall of the bore 90 and can turn no farther. As the follower cup is rotated, the actuating bar 97 will contact the plunger head 66 and move the right hand piston upward within the bore 69. As described elsewhere, the bore 69 is liquid filled and in communication with the opposite bore 75. As the har 97 moves upward, the opposite bar 93 is moved downward, permitting the left hand piston to also move downward, as fluid is forced from the area above the piston in bore 69 to the area above the piston in bore 70. The speed of upward movement of the right hand piston is determined and controlled by the position of the needle valve Si) in the transverse passage 73. The energy or force for such movement is provided by the follower spring 94 acting upon the actuating bar 97, through the follower cup 95.

As the right hand piston moves upwardly, so also does the piston rod 61 and its upper end 63, causing the valve 56 to be raised from its seat atop the orifice 43 permitting additional air to pass into the chamber 44, through the various passages to the port v39, and then to the air spring 12. This additionalrair must be under a greater pressure than the air already in the spring 12, and will extend the air spring to its initial position.

As the air spring extends, the upper frame members 15 and 16 move upwardly from the axle housing l, causing the actuating shaft 25 to be turned by the actuating rod 24 in a clockwise direction as viewed in Fig. 7. As the shaft 25 begins to assume the normal position shown in Fig. 3, the follower spring 94 will urge the plunger cup 92 downward, which action permits the follower cup 95 to begin to assume its normal position. The force which has been directing the actuating bar 97 upward, and bar 98 downward is reversed in direction, the iiow of hydraulic uid thus being reversed so that the uid will move from the area above the left hand piston to the area above the right hand piston. This lowers piston rod 61 and allows spring 5S to close the valve 56, stopping the ow of additional air and maintaining the original .position of the air spring. The spring 73 within the bore 69 assists in returning the right hand piston to its normal position as equilibrium is being reached, thus adding to the stability of the device.

Y If the static load on the vehicle suspension is decreased, the frame members 15 and 16 move upwardly away from the axle housing 18, causing the air spring 12 to extend. During this upward movement of the upper frame members, the frame member 30 and the control device 10 also move upwardly. Such upward movement of the control device 10 causes the actuating shaft 25 to be rotated by the actuating rod 24, in the clockwise direction as viewed in Fig. 5, said rod sliding with respect to the bolt 23 as the device 10 moves upwardly.

Referring specifically to Fig. 5, as the shaft 25 is rotated clockwise on its axis, transverse of the bore 9G, the plunger cup 92 will be displaced upwardly within the follower cup 95, compressing further the follower spring 94. The ensuing action is identical but opposite to that described in connection with Fig. 7. That is, as the follower cup 95 is turned on the same axis as that of the shaft 2-5 and displaced upwardly to assume the position shown in Fig. 5, the actuating bar 98 contacts the piston head 66' and moves the left hand piston upward within the bore 70. This displaces Huid from above the left hand piston to above the right hand piston. As the left hand piston moves upwardly, so also does the piston rod 62 and its upper end 63, causing the valve 57 to be raised from its seat atop the orifice 49, permitting air to exhaust from the air spring 12, through the two-way port 39, the lateral passage 51, the bore 48, the chamber 5t?, the passage 52 and the exhaust port 36, to the vatmosphere. The exhaust of air from within the spring 12 will contract the air spring to its initial position.

As the air spring contracts, the upper frame members 15 and 16 move downwardly toward the axle housing 18 causing the actuating shaft to be rotated by the actuating rod 24 in a counter-clockwise direction as viewed in Fig. 5. The ensuing action at this point is also identical but opposite to that described in connection with Fig. 7. rfhat is, the force of the spring 94 urges the plunger cup 92 downward and the follower cup 95 begins to assume its normal position. The force on the actuating bar 9S is reversed in direction and the uid will begin to ow from the area above the right hand piston to the area above the left hand piston. This lowers piston rod 62 and allows spring 59 to close the valve 57, stopping the exhaust of air and maintaining the original position of the air spring. The spring 73, within the bore 70 assists in returning the piston 68 to its normal position.

Wlienafvehicle equipped With asuspension system-- will move up and downover bumps and into holes in theV ever, as shown in Fig.' 6, a quick rotation of the shaft 25 will not cause the various components of the control device l@ to react to supply'or exhaust air because of the damping or time delay `effect of the pistons 166 upon upward Y movement Vof'the'piston rods 61 and 62. Thus, the admission of VVadditional air to or exhaust of air from the air spring 12 will Vnot occur until a force is maintained in one direction for apredetermined period of time which canbe controlled by the needle valve 80 in the fluid transfer passage 7S.V After the several springs in the device are balanced, it will be foundV desirable to choose a needlefvalve 86 which wili provide a time lag of about 7 secondsbefore the follower cup 9S will move from the normal ormiddleV position'shown in Fig. 3, to that shownrin either Figs. orV 7. However, the time delay maybe selectedany place within the preferred range of from l to seconds. A shut off valve (not shown) can be provided in the air spring line 34 so that an operator can shut off the line when raising the vvehicle by a bumper jackto remove atire.

While a been shown it will be apparent that changes and modifications, other than those specifically noted herein, could be preferred embodiment ofthe invention has made without departing from the basic principles of the invention. Therefore, the annexed claims are intended to embody therein changes of such nature. Y

What is claimed is:

1. Controlmeans adapted for regulation Vof the supply. and exhaust of air to and from'an expansible bellows* air supply port, an air exhaust port and atwo-way port,

with passageways connecting said supply portV with said two-way port and said exhaust port with said two-way port,'valves within said housing closing said passageways, parallel pistons movable upwardly within the housing to opensaid valves, that portion of the: housing between said pistons having walls defining a borebetween and parallel'with said pistons, a shaft extending transversely of said bore adapted for rotation by relative movement between the road gear and frame of the vehicle, shaft follower means within said bore responsive to movement of said shaft, and actuating means for said pistons aiixed tov said yfollower means below said bore and extending laterally thereof beneath said ',pistons, said actuating means selectively actuating one of said pistons to open one of said valves.

Y 2. Control means adapted for regulation of thek supplyV .and exhaust of air to and from an expansible bellows for a vehicle suspension system to maintain a predeter-Y mined'height between the road gear and frame of the vehicle, comprising, a housing, said housing having an air supply port, an air exhaust port and a two-way port,

Y with passageways connecting said supply port with said f said pistons having Walis a bore between parallel with said pistons, a shaft extending transversely of said bore adapted for rotation by relative movement between the road gear and frame of the vehicle, a

plunger cup; slidable fin lsaid bore aicompressed follower i spring: withinsaid plunger cup urginggthe latter `into conf-4 tact:with said shaft, ajfollower.- cupsurroundingsaid plunger cup andafollower spring,- and being lurged by said` springl in the opposite direction fromsaid;followerccup,l and apairv of actuating bars affixed to said follower cupv below Ysaid bore; and extending llaterally thereof beneath said pistons, said actuating bar selectively actuating one of'saidpistonsV to open one of said valves.'Y

3. Control means 4adapted for regulation ofthesupplyV and exhaust of air to and V from an expansibleA bellows for a vehicle suspension system to maintainV a predetermined heightY between the road gear and frame ofV said vehicle, comprising, ahousing, valves insaidhousing controlling said supply and exhaust of air, a pair of parallel Vpistonsl movable'upwardly within the housing to actuavte said valves, a shaft betweenV said pistonsadapted forrotation by relative movement between Ythe road gear and frame,v of the vehicle, oscillatable pistonV operating members 'op-y eratively connected tosaid shaft'toY actuate said valvesl when saidshaft is rotated, a lpassageway in said housing connecting the areasl above eachof saidepistons, and means including a liquid completely fillingsaid passage, way and areas above said pistons operable when one of said pistons is moved upwardly to move the other-of said pistons, downwardly.

4. Control means adapted fof regulation ofthe supply and exhaust of air to and from an expansible bellows for a vehicle suspension system to maintain a predetermined height between the road gear and frame of said vehicle, comprising, a housing, valves in said housing controlling said supply and exhaust of air, paralle1 pistons movable upwardly within the housing to actuatesaid valves, a shaft between said pistonsadapted for rotationl by relative movement between the road gearv and frame `of the vehicle, said shaft having a flattened ,Upper surface,

an inner cup above said flattened shaft surface, anouter.

cup telescopically enclosing said inner cup and shaft, a

spring interposed between said cups urging said inner cup against said flattened shaft surface, and actuatingbars affixed to said outer cup and extending laterally thereof to actuate said pistons.

5.,In combination'with a control device for regulation of the supply and exhaust of air to and from'an expansible bellows for avehicle suspension system to maintain a predetermined height between the roadkgear and frame of saidvehicle, said device including a housing and valves withinsaid housing controlling said Vsupply and exhaust of air, a shaft extending transversely Iof said housing and adapted forvrotation by relative movement between the road gear and frame of the vehicle, said shaft having a flattened surface, an inner cup adapted to seatV on saidV Y flattened shaft surface, an Vouter cup .telescopically enclosing said inner cup andv shaft, a spring interposed between said cups urging said inner cup against said flattened shaft surface, and valve actuating means connected to'said outer cup. i

References Cited in the tile of this .patent Germany of 1915 vastm- Mt 

